Back-gap controlling apparatus for compressor

ABSTRACT

A back-gap controlling apparatus for compressor is proposed to reduce an initial torque for the motor of a compressor. A high pressure between the two scroll units of the compressor can temporarily separate the two scroll units. The casing pro se or a sealing buffer can be used to limit a displacement amount of the scroll unit The excessive displacement of scroll unit can be prevented to enhance lifetime of motor.

BACKGROUND OF THE INVENTION

The present invention relates to a back-gap controlling apparatus for a compressor, and more particularly to back-gap controlling apparatus for a compressor to temporarily separate two scroll units of the compressor, thus reducing initial torque to operate the motor and limiting a displacement amount of scroll unit.

The scroll compressor generally comprises two scroll units in spiral shape, wherein one scroll unit is fixed and referred to as fixed scroll, and another scroll unit has rotational movement with respect to the fixed scroll and is referred to as orbital scroll. The two scroll units are engaged each other and have 180-degree phase difference.

The orbital scroll has rotation around the fixed scroll, thus forming closed space therebetween. A working fluid is shrunk, within the closed space, from peripheral to center, and then ejected out of the two scroll units. In this way, the compression stroke is provided.

In above-mentioned operation, the orbital scroll is driven by a driving member. It is well known that a static friction coefficient is larger than a dynamic friction coefficient for moving a body. Therefore, a larger force is required to move the orbital scroll. The driving member requires large torque to overcome a static friction between the orbital scroll and the static scroll. The driving member has risk of damage and the lifetime of the driving member is reduced.

SUMMARY OF THE INVENTION

The present invention provides a back-gap controlling apparatus for compressor to prevent an excessive displacement amount of the orbital scroll and the fixed scroll of the compressor and to prevent fluid leakage.

Accordingly, the present invention provides a back-gap controlling apparatus for compressor. The back-gap controlling apparatus comprises a casing comprising an accommodation space therein; an orbital scroll arranged in the accommodation space; and a fixed scroll arranged in the accommodation space and engaged with the orbital scroll. A compressed fluid pressure due to an operation between the orbital scroll and the fixed scroll will push the fixed scroll away from the orbital scroll. An abutting section to limit a displacement amount of the fixed scroll is provided between the casing and the fixed scroll.

BRIEF DESCRIPTION OF DRAWING

The features of the invention believed to be novel are set forth with particularity in the appended claims. The invention itself however may be best understood by reference to the following detailed description of the invention, which describes certain exemplary embodiments of the invention, taken in conjunction with the accompanying drawings in which:

FIG. 1 shows a sectional view of the first preferred embodiment of the present invention.

FIG. 2 shows the first preferred embodiment of the present invention before balance.

FIG. 3 shows the first preferred embodiment of the present invention after balance.

FIG. 4 shows a sectional view of the second preferred embodiment of the present invention.

FIG. 5 shows a sectional view of the third preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows a sectional view of the first preferred embodiment of the present invention. The present invention provides a back-gap controlling apparatus for compressor. The compressor comprises a casing 10 composed of a first shell 101 and a second shell 102 below the first shell 101. The inner diameter of the first shell 101 is equivalent to the inner diameter of the second shell 102 to define an accommodation space for accommodating other elements in the compress. An orbital scroll 20 is placed in the casing and connected to a driving member 40. A fixed scroll 30 is arranged in the casing 10 and engaged with the orbital scroll 20. A floating oil seal 70 is provided atop the fixed scroll 30. When the orbital scroll 20 and the fixed scroll 30 begin to operate, a fluid pressure generated by compression will push the fixed scroll 30 away from the orbital scroll 20. Moreover, an abutting section 50 is provided between the orbital scroll 20 and the fixed scroll 30 to limit the displacement amount of the fixed scroll 30, thus providing the back-gap controlling apparatus according to the present invention. In one preferred embodiment of the present invention, the abutting section 50 is a baffle plate placed within the first shell 101 and atop the fixed scroll 30 and the oil seal 70, thus limiting the axial displacement amount of the fixed scroll 30.

FIGS. 2 and 3 show the first preferred embodiment of the present invention before and after balance, respectively. The oil seal 70 can be pushed upward when the driving member 40 is rotated. At this time, a back pressure chamber 80 is defined by the oil seal 70 and the fixed scroll 30. Moreover, the oil seal 70 and a baffle plate screwed to the casing 10 will separate a high pressure chamber 90 and a low pressure chamber 91. When the fixed scroll 30 is pushed away from the orbital scroll 20, the contact area between the orbital scroll 20 and the fixed scroll 30 can be reduced. Therefore, the static friction is reduced. As already mentioned, to move a body in rest state needs larger force in comparison to move a body in moving state. Therefore, less rotational force is required to keep an already-moving body in moving status. The body will achieve rotational balance within shorter time. Because the fluid pressure will push the fixed scroll 30 away from the orbital scroll 20, the driving member 40 will fast achieve rotational balance by less torque.

Moreover, the fixed scroll 30 is pushed away from the orbital scroll 20 until the fixed scroll 30 is in contact with the baffle plate when the compressor begins to operate. This can prevent excessive displacement of the fixed scroll 30 and pressure leakage. Afterward, when the driving member 40 achieves rotational balance, the high-pressure fluid in the back pressure chamber 80 will provide force to push downward the fixed scroll 30. Therefore, the fixed scroll 30 has downward movement until the fixed scroll 30 is again engaged with the orbital scroll 20, as shown in FIG. 3. In this situation, friction is still present between the orbital scroll 20 and the fixed scroll 30. However, the friction is far smaller than the static friction accounting for rest body because the driving member 40 is in rotational balance.

FIG. 4 shows a sectional view of the second preferred embodiment of the present invention. The second preferred embodiment is different to the first preferred embodiment in that the inner diameter of the first shell 101 is smaller than the inner diameter of the second shell 102. An abutting section 50′ of another type is directly formed on a bottom peripheral of the first shell 101. Therefore, the abutting section 50′ will limit the displacement of the fixed scroll 30 when the fixed scroll 30 is pushed away from the orbital scroll 20.

FIG. 5 shows a sectional view of the third preferred embodiment of the present invention. The third preferred embodiment is different to previous preferred embodiments in that a sealing buffer 60 is provided between the first shell 101 and the second shell 102. The sealing buffer 60 is of annulus shape and has inner diameter the same as the inner diameter of either the first shell 101 or the second shell 102. Moreover, the inner diameter of the sealing buffer 60 can be set between the inner diameter of either the first shell 101 and the second shell 102. The sealing buffer 60 can buffer a contact between the fixed scroll 30 and the first shell 101, therefore the operation noise and component abrasion can be prevented.

The back-gap controlling apparatus according to the present invention has following advantages. There is higher pressure between the orbital scroll and the fixed scroll when the compressor begins to operate. The pressure will temporarily separate the orbital scroll and the fixed scroll to reduce contact area between the orbital scroll and the fixed scroll. Therefore, friction between the orbital scroll and the fixed scroll can also be advantageously reduced. The initial torque for operating the compressor can also be reduced and the driving member can fast achieve rotational balance. The lifetime of the compressor can be enhanced. The compressed fluid pressure due to operation between the orbital scroll and the fixed scroll will push the fixed scroll away from the orbital scroll and the fixed scroll has axial contact with the casing. The initial torque for operating the motor can be reduced and the liquid leakage due to excessive displacement can be prevented. The lifetime of motor can be enhanced and the excessive displacement of scroll unit can be prevented.

Although the present invention has been described with reference to the preferred embodiment thereof, it will be understood that the invention is not limited to the details thereof. Various substitutions and modifications have suggested in the foregoing description, and other will occur to those of ordinary skill in the art. Therefore, all such substitutions and modifications are intended to be embraced within the scope of the invention as defined in the appended claims. 

1. A back-gap controlling apparatus for a compressor, comprising: a casing comprising an accommodation space therein; an orbital scroll arranged in the accommodation space; and a fixed scroll arranged in the accommodation space and engaged with the orbital scroll; wherein a compressed fluid pressure due to an operation between the orbital scroll and the fixed scroll will push the fixed scroll away from the orbital scroll; and wherein an abutting section to limit a displacement amount of the fixed scroll is provided between the casing and the fixed scroll.
 2. The back-gap controlling apparatus for the compressor as in claim 1, wherein the casing comprises a first shell and a second shell connected to a bottom of the first shell and a floating oil seal is provided atop the fixed scroll.
 3. The back-gap controlling apparatus for the compressor as in claim 2, wherein an inner diameter of the first shell is equivalent to an inner diameter of the second shell, the abutting section is a baffle plate arranged within the first shell and placed atop the fixed scroll and the floating oil seal.
 4. The back-gap controlling apparatus for the compressor as in claim 2, wherein an inner diameter of the first shell is smaller than an inner diameter of the second shell, the abutting section is a baffle plate arranged within the first shell and placed atop the fixed scroll and the floating oil seal.
 5. The back-gap controlling apparatus for the compressor as in claim 2, wherein an inner diameter of the first shell is smaller than an inner diameter of the second shell, the abutting section is directly formed on bottom peripheral of the first casing.
 6. The back-gap controlling apparatus for the compressor as in claim 5, further comprising a sealing buffer at a junction between a first shell and a second shell.
 7. The back-gap controlling apparatus for the compressor as in claim 6, wherein the sealing buffer is of annulus shape and has an inner diameter the same as an inner diameter of the first shell.
 8. The back-gap controlling apparatus for the compressor as in claim 6, wherein the sealing buffer is of annulus shape and has an inner diameter the same as an inner diameter of the second shell.
 9. The back-gap controlling apparatus for the compressor as in claim 6, wherein the sealing buffer is of annulus shape and has an inner diameter smaller than an inner diameter of the first shell and larger than an inner diameter of the second shell. 